Control of microwave emission from photonic crystals by lattice modifications.

Abstract

Millimeter order photonic crystals composed of epoxy lattices including titania-based particles with a three-dimensional diamond structure were fabricated by using a stereolithograpy of CAD/CAM process. The diamond lattice structure formed a perfect bandgap to microwave transmission, while the directional diamond structures with stretched lattice spacing showed the directional transmission of microwave. Stretching ratio of the lattice spacing was changed according to the band calculation using a plane wave propagation method. A microwave antenna head composed of normal and stretched diamond structures was fabricated which can realize the unidirectional transmission.